This invention relates to a method for the adhesion of oxide type ceramics and copper or a copper alloy, and more particularly, a method for causing oxide type ceramics and copper or a copper alloy to adhere to each other with extremely high strength by a simple procedure.
Generally ceramics is excellent in heat resistance, wear resistance, and insulation but vulnerable to impacts. When it is used as structural material, therefore, it is used more often in the form of a composite with a metallic substance than otherwise.
Ceramics is deficient in electroconductivity. When it is used in an application necessitating electroconductivity, it is similarly used in the form of a composite with a metallic substance.
The metal which meets these two requirements most faithfully is copper or a copper alloy. The composite of ceramics and copper or a copper alloy proves most useful in applications entailing these requirements.
The present inventors have conducted a series of study on methods for the adhesion of oxide type ceramics and copper or copper alloys. They have proposed a method which comprises heating a foam of oxide type ceramics-copper or copper alloy-nickel in an oxidative atmosphere without use of any adhesive agent and subsequently allowing the heated foam to cool off gradually as disclosed in Japanese Patent Publication No. 58-3999.
By this method obtained can be amply strong adhesion of oxide type ceramics and copper or a copper alloy. The inventors have made a further study for the purpose of developing means of improving the adhesive strength. They have consequently found a method capable of improving the adhesive strength by more than 40% as compared with the adhesive strength obtained by the steps of heating and gradual cooling. This knowledge has led to perfection of the present invention.
Specifically, this invention is accomplished by placing oxide type ceramics and copper or a copper alloy into mutual contact, heating them in situ in an oxidative atmosphere thereby causing adhesion thereof, and then rapidly cooling the resultant composite of adhesion.